Process for the preparation of 1-carbamoyl-3-(3,5-dichlorophenyl)-hydantoins

Abstract

1. Process for the manufacture of N-substituted 1-carbamoyl-3-(3,5-dichlorophenyl)-hydantoins of the formula: ##STR1## in which R 1 =alkyl (C 1 -C 4 ) or phenyl and R 2 =H or alkyl (C 1 -C 4 ). 2. This process comprises two steps: a. reacting phosgene with 3-(3,5-dichlorophenyl)-hydantoin in an inert organic solvent medium, in the presence of an acid acceptor, in order to form 1-chlorocarbonyl-3-(3,5-dichlorophenyl)-hydantoin, and b. reacting the chlorocarbonyl formed with an amine HNR 1 R 2 in an inert organic solvent, in the presence of an acid acceptor. 3. This process makes it possible to obtain the products I, which can be used as agricultural fungicides, with good yields.

We claim: 
     
       1. A process for the preparation, starting from 3-(3,5-dichlorophenyl)-hydantoin, of a compound of the formula: ##STR8## in which R 1  is an alkyl radical containing from 1 to 4 carbon atoms or the phenyl radical and R 2  is a hydrogen atom or an alkyl radical containing from 1 to 4 carbon atoms, which comprises: in a first step, reacting phosgene with 3-(3,5-dichlorophenyl)-hydantoin in an inert organic solvent medium, in the presence of at least stoichiometric amount of acid acceptor, in order to form 1-chlorocarbonyl-3-(3,5-dichlorophenyl)-hydantoin, in accordance with the equation: ##STR9##  and, in a second step, reacting at 20°-80° C. the resulting product with a primary or secondary amine of the formula HNR 1  R 2 , in which R 1  and R 2  have the meanings indicated above, in an inert organic solvent, in the presence of an acid acceptor, in accordance with the equation: ##STR10##   
     
     
       2. A process according to claim 1, wherein the first step of the reaction is carried out at a temperature between 0° C. and the b.p. of the reaction mixture. 
     
     
       3. A process according to claim 1, wherein the acid acceptor is a tertiary amine. 
     
     
       4. A process according to claim 3, wherein the acid acceptor is triethylamine. 
     
     
       5. A process according to claim 3, wherein the acid acceptor is pyridine. 
     
     
       6. A process according to claim 1, wherein the acid acceptor is an inorganic base. 
     
     
       7. A process according to claim 6, wherein the inorganic base is an alkali metal carbonate. 
     
     
       8. A process according to claim 1 wherein 0.5 to 15 mol % based on the acid acceptor of an auxiliary agent, selected from an auxiliary base different from said acid acceptor or a transfer agent, is used in said first step. 
     
     
       9. A process according to claim 8, wherein the auxiliary agent is an auxiliary base which is different from the acid acceptor. 
     
     
       10. A process according to claim 9, wherein the auxiliary base is chosen from the group comprising triethylamine, pyridine and dimethylaminopyridine. 
     
     
       11. A process according to claim 8, wherein the auxiliary agent is a transfer agent. 
     
     
       12. A process according to claim 8, wherein the transfer agent is a quaternary ammonium derivative of the formula: ##STR11## in which: R 1 , R 2 , R 3  and R 4 , which are identical or different, each represent an alkyl radical containing from 1 to 20 carbon atoms, a cycloalkyl radical containing from 3 to 6 carbon atoms, an alkenyl radical containing from 2 to 20 carbon atoms, a hydroxyalkyl radical containing from 1 to 20 carbon atoms or an optionally substituted phenylalkyl radical in which the alkyl part contains from 1 to 6 carbon atoms, X represents a chlorine, bromine or fluorine atom or an SO 4 , SO 4  H, PO 4  H 2  or hydroxyl radical, an alkoxysulphonyloxy radical containing from 1 to 4 carbon atoms, an alkanesulphonyloxy radical containing from 1 to 4 carbon atoms, an arenesulphonyloxy radical or an alkanoyloxy radical containing from 1 to 4 carbon atoms and n is a number equal to the valency of X. 
     
     
       13. A process according to claim 12, wherein the quaternary ammonium derivative is tetrabutylammonium chloride or bisulphate. 
     
     
       14. A process according to claim 11, wherein the transfer agent is a phosphonium derivative of the formula: ##STR12## in which: R' 1 , R' 2 , R' 3  and R' 4 , which are identical or different, each represent an alkyl radical containing from 2 to 8 carbon atoms and Y represents a chlorine or bromine atom. 
     
     
       15. A process according to claim 11, wherein the transfer agent is a sequestering agent of the formula:   N-[CHR.sub.1 --CHR.sub.2 --O--(CHR.sub.3 --CHR.sub.4 --O).sub.n --R.sub.5 ].sub.3     in which: n is an integer which is greater than or equal to 0 and less than or equal to about 10 (0≦n≦10), R 1 , R 2 , R 3  and R 4 , which are identical or different, represent a hydrogen atom or an alkyl radical having from 1 to 4 carbon atoms, and R 5   represents an alkyl or cycloalkyl radical having from 1 to 12 carbon atoms, a phenyl radical or a radical --C m  H 2m  --φ or C m  H 2m+1  --φ--, in which m is between 1 and 12.   
     
     
       16. A process according to claim 15, wherein the inorganic base is associated with tris-(3,6-dioxaheptyl)-amine. 
     
     
       17. A process according to claim 1, wherein, in the second step, the amine HNR 1  R 2  is also used as the acid acceptor. 
     
     
       18. A process according to claim 1, wherein the solvent for both steps is an aromatic solvent. 
     
     
       19. A process according to claim 17, wherein the solvent is chlorobenzene. 
     
     
       20. A process according to one of claims 3 and 6, wherein the solvent for both steps is an aliphatic solvent. 
     
     
       21. A process according to claim 2, wherein the first step is carried out at a temperature of 60° C. to 130° C. 
     
     
       22. A process according to claim 21, wherein the reaction is carried out under an absolute pressure of 1 to 5 bars. 
     
     
       23. A process according to claim 1, wherein the two steps are carried out continuously in a single solvent, with any excess phosgene being degassed at the completion of said first step. 
     
     
       24. A process according to claim 1, wherein the intermediate is separated off at the end of the first step. 
     
     
       25. A process according to claim 1, wherein the acid acceptor is triethylamine or pyridine, and wherein the two steps are carried out continuously in the same solvent, with any excess phosgene being degassed at the completion of said first step.